含稀土相高温钛合金焊接接头的疲劳断裂特性

Fatigue Fracture Property of Welding Joints of High Temperature Titanium Alloy with Rare Earth Phase

研究了Ti-60合金电子束焊接接头的显微组织及稀土相的分布特征;对焊接接头高温旋转弯曲疲劳性能进行了试验研究,讨论了影响接头疲劳性能的主要因素。焊后状态下焊缝区中存在大量的α′马氏体组织,焊缝区中的稀土相颗粒弥散分布于晶界及晶内,尺寸在100～200nm。焊接接头具有较好的高温旋转弯曲疲劳性能,无焊接缺陷的接头均断裂在母材区,稀土相颗粒对裂纹的扩展具有阻碍作用。

The microstructure of EBW joints （Electron Beam Welding） of Ti-60 alloy and its rare earth phase distribution were investigated. High-temperature rotation flexible fatigue properties of the welding joints were tested and the main influencing factors were also discussed, There is a lot of α′ martensitil microstructure in the fusion zone at the post-welding state. And the rare earth particles of 100-200 nm dispersively distributed in the boundaries and grains. The obtained welding joints have better high-temperature rotation flexible fatigue properties. The joints without welding defects are all in parent metal. Rare earth phase particles can hinder the crack propagation.